The efficacy of Lactobacillus and Bifidobacterium in patients with schizophrenia: a meta-analysis

The modulation of gut microbiota through probiotics holds promise as a novel avenue for schizophrenia treatment. This study aims to analyze probiotic complementary therapy on individuals with schizophrenia systematically, to investigate probiotic efficacy, potential mechanisms, and implications for clinical practice. Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we searched in Medline, Web of Science, Embase, ClinicalTrials.gov, CNKI, VIP, and WanFang databases using keywords ("probiotics" OR "prebiotics" OR "synbiotics" OR "Lactobacillus" OR "Bifidobacterium") AND ("schizophrenia"), focused on randomized controlled trials published before July 1, 2023. Among the identified studies, 8 randomized controlled trials met the inclusion criteria, encompassing a total of 342 participants in the intervention group and 306 participants in the control group. Our analysis revealed a statistically significant reduction (p = 0.03) in the total Positive and Negative Syndrome Scale (PANSS) scores following probiotic treatment in individuals with schizophrenia. While no statistical significance was observed in individual subscales (P > 0.05), significant improvements were noted in insulin levels, Insulin Resistance Index (IRI), and glucose levels. Additionally, the Quantitative Insulin Sensitivity Check Index (QUICKI) demonstrated a significant increase (all P